Heat exchanger



Dec. 31, 1946.

W. R. MAGUIRE ETAL HEAT EXCHANGER 2 Sheets-Shet 1 Filed Oct. 2, 1940 mgzm M "aw RN MN w. R. MAGURE ETAL HEAT EXCHANGER Dec. 31; 1946.

Filed Oct. 2, 1940 2 Sheets-Sheet 2 TRS Patented Dec. 31, 1946 HEAT EXCHANGER.

Walter R. Maguire, Manhasset, and Edwin J. Lockwood, Peekskill, N. Y., assignors to Walter Maguire Company, Inc.

poration of New York New York, N. Y., a cor- Application October 2, 1940, Serial No. 359,326

3 Claims. (Cl. 257247) The present invention relates to new and useful improvements in heat exchangers and more particularly to a novel and improved apparatus for the heating or cooling of milk.

Objects and advantages of the invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practice with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims.

The invention consists in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate one embodiment of the invention, and together with the description, serve to explain the principles of the invention.

Of the drawings:

Fig. 1 is a vertical sectional view showing a typical and illustrative embodiment of the present invention; and

Figs. 2, 3 and 4 are vertical cross-sectional views taken on the lines 2-2, 3-3 and 44 of Fig. 1 respectively.

The present invention has for its object the provision of a novel and improved heat exchange unit particularly adapted. for the efficient heating or cooling of liquids. A further object of the invention is the provision of an improved heat exchange unit which can be easily and quickly sterilized and has a minimum number of points at which leakage is liable to occur, and which can be kept in service over long periods of time with a minimum of attention, aside from the sterilization necessary. Still another object of the invention is the provision of a tubular heatexchange unit in which the heat exchange tubes may be made of a highly efficient shape and are permanently and immovably attached to the end walls at the ends of the tubes. The invention also provides an improved tubular heatexchange unit in which the tubes are capable of relative movement due to differences in expansion without danger of the loosening of packed joints, such as are commonly used.

In accordance with the present invention, and as shown in the illustrative embodiment of the invention, the heat exchange unit comprises a plurality of pairs of liquid conducting tubes, each pair comprising an inner and an outer tube of dissimilar cross section, one of the tubes being adapted to contain the liquid to be treated, while the other of the pairs of tubes is adapted to con.-

tain the other liquid to which or from which heat is to be transferred. Headers are arranged at each end of the heat exchange unit to provide for communication between the respective tubes to conduct the liquid to be treated and the respective tubes to conduct the heat transferring liquid,

without the danger of intermixture of the two liquids, and these headers comprise spaced apart walls, partitions or plates, the outer tubes of the various pairs of tubes being securely-attached to the innermost walls, while the inner tubes are similarly attached to an intermediate wall. The

outer wall is removable so that unobstructed access may be had to the inner conducting tubes.

Preferably, the inner and outer tubes are completely Welded at their ends to their respective walls, and the space between these walls serves as a header or conduit for the heat transfer fluid,

while the space between the intermediate and outer Walls serves as a conduit for the fluid to be treated so that the latter fluid may be circulated in therma1 contact with the heat exchange medium. Intermediate the ends of the outer tubes, and preferably close to their central portions, the outer tubes are provided with an expansible corrugated portion of flexible metal so that a portion of the expansion and contraction of the outer tube may be taken up at the central portion of the outer tubes, thereby reducing he amount of movement required at the end walls. In'accordance with the illustrative embodiment,

the outer tubes are preferably, of circular cross section throughout the major portion of their length while the inner tubes are preferably of' elliptical cross section so as to increase their surface area relative to their capacity, and at the same time insure a more thorough mixing of the moving liquids due to the increased amount of liquid retarded in flow by the skin friction of the pipe.

It will be understood that the foregoing general description and the following detailed description as Well, are exemplary and explanatory of the invention but are not restrictive thereof.

Referring now in detail to the typical and illustrative embodiment. of the invention shown in the accompanying drawings, there is provided a plurality of inner tubes l0 arranged one above the other in vertical alinement, and each of these inner tubes is surrounded by a somewhat larger 6 H P o din a space for the flow of liquid on all sides of the inner tubes H]. Preferably, the inner tubes H] are elliptical in cross section with their major axes considerably greater than,

7 their minor axes. The inner tubes preferably are of uniform cross section throughout their length so that they may be easily and thoroughly cleaned and sterilized, while the outer tubes are preferably of a uniform circular cross section throughout the major portion of their length but are provided with reduced and tapering ends of elliptical cross section. These tubes may be made of stainless steel or other suitable material.

At each end of the structure is provided a narrow inner vertical wall I5, and this wall is apertical ends of the inner tubes III, and these inner tubes ID are welded to the apertures in Walls I! to provide liquid-tight joints. The space between the inner walls I5 and the intermediate header walls I1 is preferably substantial and is largely dependent upon the volume of liquid to be passed between the tubes II] and II, and the ends of the tubes II) are preferably flush with their respective walls I'I.

Means are provided for closing the ends of the tubes In so that liquid may be supplied thereto and removed therefrom, and .its flow directed backand forth through successive tubes. As embodied. an outer header wall forming a cover plate is provided at the left-hand end of the unit and has a short pipe 24 extending therefrom through which liquid may be supplied to the uppermost tube Ill and another pipe 25 through which liquid may be removed from the lowermost tube. Side and end edge walls 2| shown in section in Figure 2 and in part in Fig. 1 space the cover plate from the vertical wall I! to provide a liquid passageway therebetween, the edge walls 2| also serving to form a liquid-tight closure between the cover plate 20 and the outer face of wall I'I. Between the side edge walls 2|, and dividing the liquid passageway into compartments are a plurality of narrow removable webs 23 extending from the cover plate 20 to the vertical wall II. These are illustratively shown as positioned between the topmost and second tubes I0, between the third and fourth, the fifth and sixth, the seventh and eighth, the ninth and tenth, and the eleventh and last tubes I0, thereby dividing the tubes into pairs so that the liquid discharged from the second tube will be reversed in flow through the third tube, and so forth, although the webs 23 may be otherwise positioned to provide the desired circulation. Also the circulation may be varied by substituting one cover plate for another with the webs 23 in different positions. Or alternatively the webs 23 may be repositioned in their cover so as to provide for a different circulation of the liquid,

At the right hand end of the heat exchange unit a similar cover plate 21 is provided which differs from the one just described in that it is not provided with inlet and outlet pipes 24 and 25, and the partitioning webs 23 are provided between the second and third, the fourth and fifth inner tubes, and so forth, thereby providing a continuous liquid pathway back and forth across the heat exchange unit of the uppermost inner tube III to the lowermost inner tube. Cover plates 20 and 21 are secured to their respective vertical walls I1 by means of the studs 28 passing through efficiency apertures in the .cover plates, and by the wing nuts 29.

Means are provided for supplying heat transfer medium to the space between the tubes I0 and II, and. this medium may be either a heating or a cooling liquid. For this purpose the vertical wall I5 at the left hand end of the unit is provided with an inlet 30 communicating with the space between walls 15 and I1 near the bottom of the unit, and an outlet 3I similarly positioned but at the top of the unit.

'Means are provided for making a liquid-tight seal between the inner and intermediate walls I5 and I1 respectively .in order to provide for the circulation of the heat exchange liquid, and these means are preferably side walls 32 extending the length of the unit between the interme diate walls I! and sealingly attached, as by welding, to walls I5 and I! along their length at their edges, and inwardly bent at both ends to join each other in arcuate end seals, as shown in Fig. 3, thus completing the closure of the circulation chamber or liquid passageway formed by members I5, I1 and 32. In the circulation chamber thus formed at the left end of the heat exchanging unit thin Webs 36 are attached to and have sealing engagement with the four walls of the chamber between the openings to the third and fourth outer tubes, and the openings to the ninth and tenth outer tubes. A similar web 31 is provided in the chamber at the right of the unit be-, tween the openings to the sixth and seventh outer tubes.

Thus the heat exchange liquid supplied through the inlet 30 flows through the three lowermost outer tubes II into the space at the right hand end of the unit between the walls I5 and I1, and is thence reversely directed through the next group of three outer tubes II to the space between the left hand walls I5 and I1. Once again the flow of the heat exchange liquid is reversed and it flows through the third group of three outer tubes II to the right hand end of the unit and it is finally reversed so as to flow through the upper group of three tubes I I to the space between the walls I5 and IT at the upper end of the unit and thence the heat exchange liquid is discharged through the pipe 3|. The flow of the .heat exchange liquid is generally and preferably counter to that of the flow of the liquid in tubes I0 to be heated or cooled.

In order to reduce the amount of movement required between the walls I5 and I1, without restricting the relative expansion and contractionof the tubes I II and H, the outer tubes H are preferably formed in two sections with a slight space between their adjacent inner ends near the center of the tubes, and these adjacent ends are permanently interconnected by means of expansible corrugated sections 35 of thin resilient metal, the ends of these expansible sections being welded or otherwise sealed to the ends of tubes I I. In order to economize on space, the expansible sections 35 are staggered slightly with, alternate tubes so as to permit closer spacing of the tubes.

Suitable means are provided to increase the of the heat exchange unit and for this purpose the entire unit is enclosed at its sides,

top and bottom within walls 4|) of heat insulating material which lies within walls 32.

As shown in Fig. 1, webs 23 are provided with holes 26 through their thickness in order to provide for the drainage of fluid being treated to the bottom of the unit when introduction of the fluid into the unit through inlet pipe 24 is terminated, the holes being of sufl'iciently small diameter so that circulation of the fluid through the tubes I will not be materially afiected when the unit is in use. The tubes l0 and II are slightly inclined from the horizontal in order to impart a certain gravity flow to the fluid within the tubes to aid in circulation when the unit is in use and to efi'ect drainage of those tubes when not in use. As may be seen in Fig. 1, the topmost set of tubes l0H is downwardly inclined from adjacent the intake pipe 24 to the right end of the unit, while the next set of tubes I0ll immediately below is oppositely inclined, the third set being oppositely 'inclinedto the second set, and the remaining sets being similarly disposed with relation to each other.

When it is desired to sterilize the apparatus, it is only necessary to remove the wing nuts 29, the couplings to the pipes 24 and 25, and then the cover plates 20 and 21' may be separately removed and can be thoroughly scrubbed and washed. The webs 23 may also be removed from the cover to facilitate sterilization of the cover plates. With the cover plates removed, free access is afforded to the tubes [0 at each of their ends, and as they are of uniform section throughout their length, they may be thoroughly washed and swabbed. or otherwise sterilized.

The invention in its broader aspects is not limited to the specific mechanism shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What we claim is:

1. In a heat exchanger, the combination of a pair of headers; and, superposed closely spaced pairs of nested tubes connecting the headers, the tubes of each pair being of dissimilar contour, the outer tube of each pair being of circular cross section throughout a major portion of its length and having its ends of substantially elliptical cross section whereby close spacing of said pairs of tubes may be eifected.

2. In a heat exchanger, the combination of a pair of headers; and, superposed closely spaced pairs of nested tubes connecting the headers, the inner tube of each pair being of uniform elliptical cross section throughout its length, the outer tube being of circular cross section throughout a major portion of its length and being formed of two sections interconnected by a flexible extensible member, the remote ends of said sections being of elliptical cross section with the minor axis of each ellipse lying in the plane of the axes of said tubes.

3. In a heat exchanger, the combination of a pair of header compartments having a common partition wall, a plurality of tubes communicating with one of said compartments, said tubes being circular in cross section throughout a major portion of their length, and a plurality of tubes of elliptical cross section each of which communicates with the other of said compartments and is positioned within a difierent one of said first mentioned tubes.

WALTER R. MAGUIRE. EDWIN J. LOCKWOOD. 

